1. Field of the Invention
The present invention relates to a body-insertable device having a local injection function which is introduced into a body and injects a liquid medicine into a desired part in the body and a liquid medicine injection method.
2. Description of the Related Art
A body-insertable device which extracts body fluid in a patient has been proposed. The body-insertable device has, in a capsule-type casing, a storage chamber which stores body fluid extracted from the inside of the body, and an input controlling mechanism which controls an input of the body fluid to the storage chamber. Upon reaching a desired part in the body such as a patient, the body-insertable device extracts the body fluid by predetermined control of the input controlling mechanism, and then stores the extracted body fluid in the storage chamber.
As a specific example of such a body-insertable device of the related art, there has been proposed a body-insertable device which has an extracting needle having, at its tip, an extracting portion having water absorbing properties, a driving mechanism which projects and houses the extracting needle from and in a casing, and a projection/housing controlling mechanism which controls the projecting operation and the housing operation of the extracting needle by the driving mechanism by an electromagnetic force (see Japanese Published Examined Application No. 57-39776). According to control of the projection/housing controlling mechanism, the driving mechanism of the body-insertable device projects the extracting needle from the casing, allows body fluid to adhere to the extracting portion at the tip of the extracting needle, and houses the extracting needle in the casing together with the extracting portion to which the body fluid adheres. In this manner, the body-insertable device extracts body fluid in the desired part in the body.
There has been also proposed a body-insertable device which directly supplies a liquid medicine to an affected part in the body by application of the above mechanism. The body-insertable device has an injection needle in place of the extracting needle of the body-insertable device described in Japanese Published Examined Application No. 57-39776, projects the injection needle from a casing, and then discharges the liquid medicine via the injection needle. In such a body-insertable device, the injection needle projected from the casing punctures the affected part in the body, and then injects the liquid medicine into the affected part.